What is the least common multiple of 18 and 15? Another way to say this is: $\lcm(18, 15) = {?}$
Answer: The least common multiple is the smallest number that is a multiple of 18 and 15. We know that 18 x 15 (or 270) is a common multiple, but is it the least common multiple? Write out the multiples of 18 until we find a number divisible by 15. 18, 36, 54, 72, 90, So, 90 is the least common multiple of 18 and 15.